It's worth what it is worth to the person buying it, the cost of fabs and mods never factor in the resale price, I've spent well over $10K building a 1971 510/1600 wagon with a VG30DETT and when I sold it I got $6K but this was before eBay.

So a great way of seeing what it is worth is to put it on an eBay auction start with a $1K bid then see where it goes.